Genetic inheritance is a known risk factor for endometriosis. Because microRNAs (miRNAs) are important regulators of gene expression, FI Branch-supported investigators focused on small changes in the DNA binding sites of 22 miRNAs previously linked to endometriosis. Visit Genetic Sequences Provide Clues to Endometriosis Risk for more details on this finding.

Recently published findings from the study suggest that current statistics may greatly underestimate the number of women who have endometriosis. Among women seeking clinical care for endometriosis and a matched population cohort, endometriosis incidence ranged by two orders of magnitude by diagnostic method: 0.7% for histology only, 7% for MRI only, and 41% for visualized disease. The incidence of MRI-diagnosed endometriosis was 11% in the population cohort. Conservatively, then, 11% of women have undiagnosed endometriosis at the population level. These findings have implications for the design and interpretation of etiologic research, but also for the economic and overall health of the nation. (Source: Buck Louis, G. M., et al. (2011). Fertility and Sterility, 96, 360-365. PMID: 2171900.)

Epidemiology Branch researchers are also studying the origins of endometriosis, including very early origins that might start in the womb. Visit Endometriosis Risk Might Begin Early for more information on this research.

Recent findings from PRAE researchers found that women with endometriosis had a higher prevalence of recurrent upper respiratory or vaginal infections, melanoma, and ovarian cancer than the general population. (Source: Gemmill, J. A., et al. (2010). Fertility and Sterility, 94, 1627-1631. PMID: 19945097)

PRAE researchers are also working to treat the symptoms of endometriosis more effectively. In one study, researchers examined women with chronic pelvic pain and endometriosis. They found that lesion depth, disease severity (burden), and the number of lesions were not associated with pain location. Only painful urination (dysuria) and midline abdominal pain were associated with location of superficial endometriosis lesions. (Source: Hsu, A. L., et al. (2011). Obstetrics and Gynecology, 118(2 Pt 1), 223-230. PMID: 21775836)

In a clinical study from the PRAE, researchers found that daily doses of raloxifene (a hormone-like drug) given after surgery for endometriosis was less effective at reducing pain than was surgery alone. They also found that raloxifene actually shortened the time to return of chronic pain. Because recurrence of endometriosis lesions did not correlate with return of pain, other factors such as estrogen are implicated in pelvic pain. The results of this study could lead to other advances in treating pain related to endometriosis. (Source: Stratton, P., et al. (2008). Obstetrics and Gynecology, 111, 88-96. PMID: 18165396)

Investigators also found that women with endometriosis have reduced expression of four biomarkers of implantation compared to healthy controls. The investigators suggest this might indicate impaired endometrial receptivity in patients with endometriosis. (Source: Wei, Q. (2009). Fertility and Sterility, 91(5), 1686-1691. PMID: 18672236)

Other Activities and Advances

In 2013, the World Endometriosis Society Montpellier Consortium published the first-ever worldwide consensus statement on the management of endometriosis. The statement, published in the journal Human Reproduction, addresses 69 issues related to the management of endometriosis. NICHD scientists and grantees were among those on the Consortium. Visit Global Consortium Identifies Best Management of Endometriosis for more information.

Through the SCCPIR, the NICHD also supports the Endometrium Database Resource, housed at Baylor College of Medicine. Its purpose is to curate genes reported in the literature to be regulated in the uterus in human, mouse, rat, cow, guinea pig, pig, and sheep. The Resource supplies tools that allow easy comparison of relative RNA expression from different experimental conditions in curated publications to determine how those conditions affect gene expression in various layers of the uterus.

The FI Branch-supported Reproductive Medicine Network (RMN) studies issues related to infertility and reproductive health in women. Several RMN studies are examining the effectiveness of assisted reproductive technology, such as IVF, in promoting pregnancy among women who are infertile, including those who have endometriosis-related infertility.